The invention relates to an automatic dish washer with a washing chamber and a device for conveying humid air out of the washing chamber to a drying device, with the drying device comprising at least one sorption unit.
WO 2010/012709 A1 and WO 2010/052116 A1 describe automatic dish washers with a sorption drying system. Here, humid air is guided out of the washing chamber through a drying device in order to dry the dishes. For this purpose, the washing chamber is connected via at least one passage to a drying device, in order to generate an air exchange.
DE 103 53 774 A1 describes an automatic dish washer comprising a sorption column. The sorption column is used to dry the dishes. The thermal energy used for desorption is used to heat the rinsing liquid located in the washing chamber and the dishes.
Furthermore, household machines are known from DE 10 2008 054 834 A1, which operate according to the principle of a heat pump. The household machines comprise a closed system, sealed gastight from the exterior, with a cold side and a warm side.
The drying device comprises a sorption unit, which shows a material which can be reversibly dehydrated, with preferably a zeolithic material being used. After the rinsing process, during the program step “drying”, the zeolithic material accepts water vapors from the humid air of the washing chamber, which flow through the sorption unit.
After the adsorption of the water vapor during this program step the zeolithic material heats up. After the sorption unit, now the dry and warm air is returned into the washing chamber. By the use of the drying device it now shows a lower humidity, can once more be charged with water vapor maximally up to saturation, and is then again guided over the drying device. By the use of such drying devices the drying period of the dishes is considerably shortened.
The zeolithic material used in the sorption unit must be regenerated after the drying step. This regeneration is also called desorption. Here, the zeolithic material is strongly heated so that the water vapor bonded to the surface is desorbed. This regeneration process occurs only shortly before the next hot washing process because the zeolithic material otherwise would accept water vapor from the environmental air and thus showed a lower adsorption capacity.
The desorbed hot water vapor is guided into the washing chamber and here condenses at the surface of the dishes and the walls of the washing chamber. Energy is saved by utilizing this condensation heat. The energy expense for heating the washing water is therefore reduced.
Automatic washing machines with a sorption drying system are some of the most energy efficient in the world. Due to their high energy efficiency such automatic dish washers are awarded very good energy consumption ratings, which are a very important argument for many consumers when rendering a purchase decision.
During the regeneration phase here not only water vapor is desorbed but additionally the zeolithic material itself is heated. After the regeneration phase the sorption material cools only slowly by releasing heat to the environment.